The Chapters of Deceit Add-on for Army of TWO: The 40th Day has 8 achievements worth 250 gamerscore.
Escort all hostages to safety.
There are some bad ass masks lying around the city. Find one or two to change your look.
Complete Chapter 8 on any difficulty level.
Complete Chapter 9 on any difficulty level.
Dr. Wu is digging up some intel for you. Make sure he stays alive long enough to find it.
Meilin Jun betrayed the civilian resistance but if it's of no consequence to you, let her live.
Meilin Jun is a snitch and a traitor. Give her what she deserves.
You've got a chance to take out Jonah, the leader of the FDI. Don't blow it.